1. Technical Field
Exemplary embodiments of the present invention relate to a test pattern and a method of monitoring defects using the same. More particularly, exemplary embodiments of the present invention relate to a test pattern that is used for setting examination procedures in a tester for detecting defects of a semiconductor device, and a method of monitoring the defects using the test pattern.
2. Discussion of Related Art
Generally, a semiconductor device may be manufactured by various processes, such as a deposition process, a photolithography process, an ion implantation process, a polishing process, a cleaning process, and the like. After completing one or more of the above-mentioned processes, a plurality of defects, such as a short, an open, and the like, may be generated in the semiconductor device. The defects may have undesirable effects on the performance of the semiconductor device. Thus, to effectively control the defects that may be generated in each of the processes, the defects need to be detected using a suitable defect detector.
Further, to determine whether the defect detector has the desired detection capacities, the detection capacities of the defect detector may be examined using a test pattern. Here, the methods used for a defect detector examination may be classified into a non-contact test process and a contact test process using a probe.
Examples of conventional methods used for the defect detector examination are disclosed in U.S. Patent Application Publication No. 2004-207414 and Japanese Patent Laid-Open Publication Nos. 2002-368049 and 1999-31727.
According to the non-contact test process, a test pattern is scanned using an electron beam. Defects in the test pattern are then detected based on the obtained scanning results.
In contrast, according to the contact test process, the probe electrically makes contact with a test pattern. An electrical signal is supplied to the test pattern through the probe. Defects in the test pattern are then detected according to the obtained electrical signals.
To enhance the accuracy in examining the detection capacity of the defect detector, a method of artificially forming and implanting defects into a test pattern has been used. For instance, defects are artificially formed in a specific portion of the test pattern, and then the detection capacity of the defection tester is examined by accurately detecting an abnormal pattern therein that has defects detected by the defect detector.
When the non-contact test process is employed, the artificially created defects may be precisely detected based on a brightness difference between a normal pattern and the abnormal pattern on the obtained scanning result. When the contact test process is employed, however, all patterns in the test pattern may be detected as abnormal patterns, because the probe makes contact with the all of the patterns. That is, since the normal pattern and the abnormal pattern in the conventional test pattern are electrically connected to each other, all of the patterns may be determined as abnormal patterns when the contact test process is performed. As a result, when the contact test process is employed, the defects may not be artificially formed in the conventional test pattern. Therefore, it may be required to prepare separate test patterns in accordance with the contact test process and the non-contact test process.
Further, since the non-contact test process and the contact test process may not be applied to the conventional single test pattern, defects between a pattern and a conductive line arranged on the pattern may not be accurately detected. For example, in the conventional single test pattern, when a pattern is formed by a chemical mechanical polishing (CMP) process, minute conductive materials may still remain between the patterns. Thus, after forming the pattern, it may be necessary to perform a subsequent process so as to carry out the defect detection process. As a result, after the conductive line is formed on the pattern by the subsequent process, the defect detection process is carried out using the conductive line. Here, since the pattern is covered with the conductive line, defects such as the minute conductive materials may be detected only by the contact test process, but not by the non-contact test process. As described above, however, the contact test process and the non-contact test process may not be applied to the conventional test pattern so that defects between the pattern and the conductive line may not be accurately detected.
Furthermore, in a conventional test pattern having alternately arranged patterns such as an NMOS contact and a PMOS contact, that have different electrical characteristics, the two kinds of the patterns may be separately scanned with an electron beam during the non-contact test process. Thus, separate information with respect to each of the patterns may not be obtained, because the electron beam may have a minimum scan width of about 100 μm, and each of the patterns may have a width of no more than about 50 μm. Therefore, patterns having different electrical characteristics may not be separately tested using the conventional test pattern.